The raiders, who were armed with tools, threatened a G4S courier at the De Montfort University campus at 6.18am yesterday.

The suspects escaped with the money in a vehicle following the raid in Mill Lane.

The courier sustained minor injuries and was taken to hospital for treatment.

Mill Lane and Gateway were cordoned off for about five hours while forensic teams combed the area.

A spokeswoman for Leicestershire Police said: "The suspects approached a security vehicle and threatened the crew before stealing a quantity of cash.

"One person received minor injuries – one of the van crew members – and was treated at Leicester Royal Infirmary."

Police said officers were still taking statements from witnesses, so could not confirm how many people were involved, what they looked like or what car they used to leave the scene.

A spokeswoman said: "Inquiries are in their very early stages, but anyone who saw any suspicious activity in the area or witnessed the incident is asked to contact the police immediately."

G4S said the courier who was attacked was recovering at home. The company would not confirm how much cash was taken. Gerry Langdale, cash regional operations director, said: "A violent attack was made on one of our cash vehicles.

"One of our couriers suffered minor injuries.

"Fortunately, he has been able to return home.

" Management is also on hand to support the crew and their families.

"We take the safety and welfare of our staff extremely seriously and work to give our crews the best possible protection.

"Our staff have the right to expect to be able to go about their duties without fear of attack.

"We are working with the police so that those responsible for this incident can be made accountable in court."

Pc Gail Warden, who patrols the campus, thanked security staff at the university for helping police officers.

She tweeted: "Thanks to security who have provided all-day assistance to aid the requests of the police."

A spokeswoman for De Montfort University said no staff or students had been affected by the incident and that all buildings were open and lectures took place as normal.

Anyone with information about the incident should call police on 101 or Crimestoppers on 0800 555111.